1 files changed, 255 insertions, 0 deletions

diff --git a/private/ntos/npfs/prefxsup.c b/private/ntos/npfs/prefxsup.c
new file mode 100644
index 000000000..4771f305f
--- /dev/null
+++ b/private/ntos/npfs/prefxsup.c
@@ -0,0 +1,255 @@
+/*++
+
+Copyright (c) 1989  Microsoft Corporation
+
+Module Name:
+
+    PrefxSup.c
+
+Abstract:
+
+    This module implements the Named Pipe Prefix support routines
+
+Author:
+
+    Gary Kimura     [GaryKi]    13-Feb-1990
+
+Revision History:
+
+--*/
+
+#include "NpProcs.h"
+
+//
+//  The Bug check file id for this module
+//
+
+#define BugCheckFileId                   (NPFS_BUG_CHECK_PREFXSUP)
+
+//
+//  The debug trace level for this module
+//
+
+#define Dbg                              (DEBUG_TRACE_PREFXSUP)
+
+#ifdef ALLOC_PRAGMA
+#pragma alloc_text(PAGE, NpFindPrefix)
+#pragma alloc_text(PAGE, NpFindRelativePrefix)
+#endif
+
+
+PFCB
+NpFindPrefix (
+    IN PUNICODE_STRING String,
+    IN BOOLEAN CaseInsensitive,
+    OUT PUNICODE_STRING RemainingPart
+    )
+
+/*++
+
+Routine Description:
+
+    This routine searches the FCBs/DCBs of a volume and locates the
+    FCB/DCB with longest matching prefix for the given input string.  The
+    search is relative to the root of the volume.  So all names must start
+    with a "\".
+
+Arguments:
+
+    String - Supplies the input string to search for
+
+    CaseInsensitive - Specifies if the search is to be done case sensitive
+        (FALSE) or insensitive (TRUE)
+
+    RemainingPart - Returns the string when the prefix no longer matches.
+        For example, if the input string is "\alpha\beta" only matches the
+        root directory then the remaining string is "alpha\beta".  If the
+        same string matches a DCB for "\alpha" then the remaining string is
+        "beta".
+
+Return Value:
+
+    PFCB - Returns a pointer to either an FCB or a DCB whichever is the
+        longest matching prefix.
+
+--*/
+
+{
+    PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry;
+    PFCB Fcb;
+
+    PAGED_CODE();
+
+    DebugTrace(+1, Dbg, "NpFindPrefix, NpVcb = %08lx\n", NpVcb);
+    DebugTrace( 0, Dbg, "  String = %Z\n", String);
+
+    //
+    //  Find the longest matching prefix
+    //
+
+    PrefixTableEntry = RtlFindUnicodePrefix( &NpVcb->PrefixTable,
+                                             String,
+                                             CaseInsensitive );
+
+    //
+    //  If we didn't find one then it's an error
+    //
+
+    if (PrefixTableEntry == NULL) {
+
+        DebugDump("Error looking up a prefix", 0, NpVcb);
+        NpBugCheck( 0, 0, 0 );
+    }
+
+    //
+    //  Get a pointer to the Fcb containing the prefix table entry
+    //
+
+    Fcb = CONTAINING_RECORD( PrefixTableEntry, FCB, PrefixTableEntry );
+
+    //
+    //  Tell the caller how many characters we were able to match.  We first
+    //  set the remaining part to the original string minus the matched
+    //  prefix, then we check if the remaining part starts with a backslash
+    //  and if it does then we remove the backslash from the remaining string.
+    //
+
+    RemainingPart->Length = String->Length - Fcb->FullFileName.Length;
+    RemainingPart->MaximumLength = RemainingPart->Length;
+    RemainingPart->Buffer = &String->Buffer[ Fcb->FullFileName.Length/sizeof(WCHAR) ];
+
+    if ((RemainingPart->Length > 0) &&
+        (RemainingPart->Buffer[0] == L'\\')) {
+
+        RemainingPart->Length -= sizeof(WCHAR);
+        RemainingPart->MaximumLength -= sizeof(WCHAR);
+        RemainingPart->Buffer += 1;
+    }
+
+    DebugTrace(0, Dbg, "RemainingPart set to %Z\n", RemainingPart);
+
+    //
+    //  And return to our caller
+    //
+
+    DebugTrace(-1, Dbg, "NpFindPrefix -> %08lx\n", Fcb);
+
+    return Fcb;
+}
+
+
+PFCB
+NpFindRelativePrefix (
+    IN PDCB Dcb,
+    IN PUNICODE_STRING String,
+    IN BOOLEAN CaseInsensitive,
+    OUT PUNICODE_STRING RemainingPart
+    )
+
+/*++
+
+Routine Description:
+
+    This routine searches the FCBs/DCBs of a volume and locates the
+    FCB/DCB with longest matching prefix for the given input string.  The
+    search is relative to a input DCB, and must not start with a leading "\"
+    All searching is done case insensitive.
+
+Arguments:
+
+    Dcb - Supplies the Dcb to start searching from
+
+    String - Supplies the input string to search for
+
+    CaseInsensitive - Specifies if the search is to be done case sensitive
+        (FALSE) or insensitive (TRUE)
+
+    RemainingPart - Returns the index into the string when the prefix no
+        longer matches.  For example, if the input string is "beta\gamma"
+        and the input Dcb is for "\alpha" and we only match beta then
+        the remaining string is "gamma".
+
+Return Value:
+
+    PFCB - Returns a pointer to either an FCB or a DCB whichever is the
+        longest matching prefix.
+
+--*/
+
+{
+    ULONG NameLength;
+    PWCH Name;
+
+    UNICODE_STRING FullString;
+    PWCH Temp;
+
+    PFCB Fcb;
+
+    PAGED_CODE();
+
+    DebugTrace(+1, Dbg, "NpFindRelativePrefix, Dcb = %08lx\n", Dcb);
+    DebugTrace( 0, Dbg, "String = %08lx\n", String);
+
+    //
+    //  Initialize the Temp buffer to null so in our termination handler
+    //  we'll know to release pool
+    //
+
+    Temp = NULL;
+
+    try {
+
+        //
+        //  We first need to build the complete name and then do a relative
+        //  search from the root
+        //
+
+        NameLength    = String->Length;
+        Name          = String->Buffer;
+
+        ASSERT(NodeType(Dcb) == NPFS_NTC_ROOT_DCB);
+
+        Temp = FsRtlAllocatePool( PagedPool, NameLength + 2*sizeof(WCHAR) );
+
+        Temp[0] = L'\\';
+        RtlCopyMemory( &Temp[1], Name, NameLength );
+        Temp[NameLength/sizeof(WCHAR) + 1] = L'\0';
+
+        RtlInitUnicodeString( &FullString, Temp );
+
+        //
+        //  Find the prefix relative to the volume
+        //
+
+        Fcb = NpFindPrefix( &FullString,
+                            CaseInsensitive,
+                            RemainingPart );
+
+        //
+        //  Now adjust the remaining part to take care of the relative
+        //  volume prefix.
+        //
+
+        RemainingPart->Buffer = &String->Buffer[(String->Length -
+                                                 RemainingPart->Length) / sizeof(WCHAR)];
+
+        DebugTrace(0, Dbg, "RemainingPart set to %Z\n", RemainingPart);
+
+    } finally {
+
+        //
+        //  Release the pool if we it was allocated
+        //
+
+        if (Temp != NULL) { ExFreePool( Temp ); }
+
+        //
+        //  And return to our caller
+        //
+
+        DebugTrace(-1, Dbg, "NpFindRelativePrefix -> %08lx\n", Fcb);
+    }
+
+    return Fcb;
+}
+